Most BIM (Building Information Modeling) technologies today disconnect the production of permit drawings from the processes for fabrication and installation. When owners include subcontractors in preconstruction services (as they often do with general contractors) they have the ability to coordinate these activities and reduce errors.
What is needed then is a data backbone to connect the building design to the fabrication detailing and installation sequences. It is common practice to have architects design a facade, independently from the manufacturer who fabricates the facade, and also independently from the general contractor and subcontractors who install the facade system.
Construction projects have included waste levels of more than 25%, and a major portion of that waste is related to the building envelope and facade. Waste consists of redundant document production, unused stored materials, idling workers, rework of installations, and other factors.
Owners and general contractors need to understand how much waste is connected to facade design engineering and planning processes.
New Contract Structure
The Design-Bid-Build relationship is the traditional contract model. Unfortunately, it makes it difficult for owners to drive project efficiency because of a lack of transparency in business processes and cost management systems.
In these circumstances, no one can take ownership of cost management over the entire life of a construction project. The Design-Build-Operate relationship is one answer to this issue.
In this form of agreement owners have the ability to coordinate the work of general contractors, subcontractors, building product manufacturers, operation and maintenance companies, and other stakeholders, in order to find a better way to deliver projects.
This approach makes building construction more like large scale product manufacturing, which historically has had much less waste.
Information Exchange Problems
When facade design engineers make fabrication documents, information exchange is a critical issue. If a building has a complex facade shape, it is important to seamlessly generate accurate 3D geometry and to produce specific 2D drawings for CNC cutting machines.
Current BIM software has limited capability to produce 3D geometry appropriate to fabrication. Therefore it makes sense for architects to access libraries of parts used by a manufacturer rather than creating similar information from scratch.
It is hard for facade design engineers to adapt to frequent design changes and reproduce facade production documents on the fly, unless they are directly connected to the architect’s model.
Installation is, of course, an important perspective from which to improve productivity. If the unique types and shapes of facade panels grow in number and variety, it becomes increasingly difficult to manage onsite installation.
If delivery sequence and installation processes of panels are not managed well onsite, it is hard to understand which panels should be installed in which positions. This could result in a large waste of time and resources.
To compound this problem neither manufacturers nor architects include cranes, scaffolds, and other installation equipment in the documents. This third data source must also be included to optimize the delivery process.
In summary, we need new contracts, new processes, and new tools to address the massive amount of waste in building construction. The separate processes of design, fabrication detailing, and installation planning need to be combined into a single environment to properly understand costs and risks in building projects. A promising solution for such an environment is on the cloud.
Watch an 8-minute demo of Dassault Systèmes’ technology platform dedicated to Façade Design for Fabrication, Integrated Planning and Façade Detailing